Piezoelectric vibration device

Abstract

A piezoelectric vibration device is provided that includes a piezoelectric vibration piece and a housing in which the piezoelectric vibration piece is containable. The piezoelectric vibration device further has electrically conductive pads formed on a surface of the housing to which the piezoelectric vibration piece is mountable. The piezoelectric vibration piece is bonded to the electrically conductive pads using metal bumps. An outer surface of the cabinet opposite to the mounting surface is dented toward the mounting surface so as to form a space that overlaps with the electrically conductive pads in plan view.

1 . A piezoelectric vibration device, comprising:
 a piezoelectric vibration piece;   a cabinet with a housing in which the piezoelectric vibration piece is containable; and   an electrically conductive pad on a mounting surface of the housing to which the piezoelectric vibration device is mountable,   the piezoelectric vibration piece being bondable with a metal bump to the electrically conductive pad,   an outer surface of the cabinet on a side opposite to the mounting surface is recessed toward the mounting surface to form a space in a region that overlaps with the electrically conductive pad in plan view.   
     
     
         2 . The piezoelectric vibration device according to  claim 1 , wherein the piezoelectric vibration piece is a piezoelectric vibration piece in the form of a tuning fork. 
     
     
         3 . The piezoelectric vibration device according to  claim 1 or 2 , further comprising an external terminal on an outer bottom surface of the cabinet, wherein
 the external terminal is formed in a region with no overlap with the electrically conductive pad in plan view.   
     
     
         4 . The piezoelectric vibration device according to  claim 3 , wherein
 the cabinet comprises a base member and a lid member,   the base member comprises the external terminal and the mounting surface on which the electrically conductive pad is formed, and   the lid member is bonded to the base member to seal the housing,   the base member further comprises:   a substrate portion;   a first frame portion; and   a second frame portion,   the first frame portion is formed in an annular manner in an outer periphery of one main surface of the substrate portion,   the second frame portion is formed in an annular manner in an outer periphery of another main surface of the substrate portion,   the lid member is bonded to an upper end surface of the first frame portion,   the housing is formed by the substrate portion, the first frame portion and the lid member form, and   the external terminal is formed on a lower end surface of the second frame portion.   
     
     
         5 . The piezoelectric vibration device according to  claim 4 , wherein
 a region defined by an inner peripheral edge of the second frame portion on the another main surface of the substrate portion of the base member has a greater dimension in plan view than a region defined by an inner peripheral edge of the first frame portion on the one main surface of the substrate portion.   
     
     
         6 . The piezoelectric vibration device according to  claim 4 , wherein
 the substrate portion and the second frame portion form a housing recess in which an integrated circuit element is containable,   the integrated circuit element is mounted to the another main surface of the substrate portion, and   a region mounted with the integrated circuit element does not overlap in plan view with a region of joint of the electrically conductive pad with the metal bump.   
     
     
         7 . The piezoelectric vibration device according to  claim 4 , wherein
 the substrate portion and the second frame portion form a housing recess in which an integrated circuit element is containable,   the integrated circuit element is mounted to the other main surface of the substrate portion, and   a region mounted with the integrated circuit element is filled with an underfill that spreads as far as a region of joint of the electrically conductive pad with the metal bump in plan view.   
     
     
         8 . The piezoelectric vibration device according to  claim 6 , wherein
 a stepped portion is formed on the one main surface of the substrate portion of the cabinet,   the electrically conductive pad is formed on an upper surface of the stepped portion to constitute the mounting surface, and   a first thickness is greater than a second thickness and the second thickness is greater than a third thickness, where the first thickness is a dimension from the mounting surface to the external terminal in a direction of thickness which is a direction orthogonal to the one main surface of the substrate portion of the cabinet, the second thickness is a dimension in the direction of thickness of a region where the electrically conductive pad is formed, and the third thickness is a dimension in the direction of thickness of the region mounted with the integrated circuit element.